1. Field of the Invention
Packaging material for packaging moisture-sensitive products, containing at least two functional layers.
2. Background Art
It is known that foodstuffs such as e.g. cheeses mature during storage, during which process gases, such as CO.sub.2, which should escape are produced; the moisture of the surroundings must be under control and the ingress of oxygen may have to be limited. In particular, in the case of soft cheeses which are enclosed in the final form of packaging immediately or shortly after production, the packaging material is very important as the cheese has to mature in the packaging and have to be ready packed for storage, handling and selling.
A packaging material e.g. for cheese, meat etc., known for example from EP-A 0 229 550, comprises a combination of a support and a material that is permeable to moisture. The support may be of paper or a micro-porous polymer or a polymer featuring micro-perforations. The material which is permeable to moisture is e.g. a polymer or copolymer based on acrylnitriles, in particular grafted polymers of amidon-polyacrylnitrile and a polyfunctional alcohol.
Such packaging materials are complicated to manufacture and can be improved upon further e.g. with respect to the materials to be used, properties and economics of manufacture.